Governing mechanism for centrifugal compressors operating in parallel.



R. TRUGER.

GOVERNING MECHANISM FOR GENTRIFUGAL GOMPRESSORS OPERATING IN PARALLEL.

APPLICATION FILED 11130.28, 1911. 1,121,956.

Patented Dec. 22, 1914.

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Comluresso'r Witnesses: I river? tor:

j a I Richard Tr'j' er, 3.1;- ;ZZ I aflmwf R. TR'O'GER.

GOVERNING MECHANISM FOR OENTRIFUGAL OOMPRBSSORS OPERATING IN PARALLEL.

APPLICATION FILED DEC. 28, 1911, I 1 21,956. Patented Dec.22,1914.-

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Witnesses:

RICHARD 'rRoGER, or OHARLOTTENBURG, GERMANY,

RLEoTRIc COMPANY, A CORPORATION OF NEW YORK.

AssI NOR TO GENERAL GOVERNING MEOHANISM FOR CENTBIFUGAL OoMrREssORs OPERATING IN 1 PARALLEL Specification of Letters Patent.

Application filed December 28, 1911. Serial No. 668,339.

ressors perating in Parallel, of which the ollowing is a specification.

In connecting centrifugal compressors for parallel operation it has been customary to bring the regulating members of the differ ent compressors into .dependence upon the pressure in the receiver or conduit into which the fluid therefrom is discharged. This arrangement has the disadvantage that within a short time the loads on the several compressors become unequal because the regulators for the compressors can never be made with the same degree of sensitiveness. Furthermore the characteristics of compressors vary, particularly those of different makes and types. The object of the present invention is to Overcome the objections above mentioned and to provide a governing or regulating mechanism for centrifugal compressors which is so-organized and arranged that the load can be properly distributed and maintained between the several compressors when the latter are connected in parallel.

-In my'improved arrangement the output regulating members of all the compressors operating in parallel are actuated by mechanism that is common thereto. This mechanism may be moved automatically in response to pressure in the pipe system, or by hand. Each regulating member is also so arranged that it can be adjusted independently of the actuating mechanism and hence of each other in accordance with the peculiarities of its compressor.

In the accompanying drawings which are illustrative of my invention, Fi ure 1 is a somewhat diagrammatic view s owingair compressors arranged to discharge in parallel intov the same header, receiver or pipe system; Fig. 2 is a detail view of a cam for actuating t e throttle valve in the intake of the'compressor; and Fig. 3 is a view of the same-taken at right an les-to that of Fig, 2.

1 indicates a centri ugal air compressor of any suitable type that is arranged to discharge air in the receiver or header 2 by means of a discharge conduit 3. It may be driven by any suitable means such as an electrio motor, steam turbine or other engine. One oremore additional compressors are arranged to discharge into the receiver, the discharge conduit being indicatedat 4; and 5. I have not illustrated these compressors for the reason that they are or may be of the same type as the one shown. Each air compressor is provided with an intake 6 in which is located a throttle valve 7 of the butterfly or other suitable type. This valve 1s mounted on a stem that is provided with. a

'crank 8 on one end and by means of which.

the valve can be adjusted within the intake. The crank is actuated by'a suitable jointed rod '9 which derives its movement from a suitably shaped 'cam 10. This cam is shaped Patente Dec. 22, 1914.

according to the characteristics of its compressor, and while the cams of all of the compressors are substantially of the same general contour, one may differ from the other to a certain extent owin to the peculiarities of the compressor wit which 1t'cooperates. Dueto the fact that these cams are relatively small and are accessible it is preferable to modify their shapes, if necessary, after the compressors have been ,installed and tested and the peculiarities of each compressor noted.

. On the shaft that carries the cam is a worm wheel-11 that meshes with a worm 12 carried by the shaft 13. On the u per-end of the shaftis a inion 14 that mes es with a bevel gear 15 w ich is loosely mounted on the shaft 16, the latter being. common to all of the compressors thatare connected to the same header or receiver. The shaft may be operated by handor sponse to changes in 2. Mounted on the s nected thereto are as many ressure in the header aft and rigidly conflanged mem- 'bers 17 as there are compressors to be controlled. Each of the said members is proautomatically in revided with a number of set screws 18'by means of which the member 17'can be connected to the flanged hub of the bevel gear 15. This gear is, as before stated, loose on the shaft 16 and is held against axial 'move' ment by the collars 19. When the screws 18 are seated, the shaft 16 and the gear wheel move as a unit. When they are released the bevel gear can be rotated by the hand wheel 20 which will adiust the cam 10 to any desired position.

n the ordinary operation of these compressors, assuming a given load condition, the cam 10 of each compressor is first adjusted to its proper position by the hand wheel 20 after which the set screws 18 are seated so that a movement of the shaft 16in one direction or the other will cause a movement of the cam 10 and also of the throttle valve 7 on each compressor. The flanged member 17 and the cooperating hub of the gear 15 form a clutch by means of which the actuating shaft 16 and the regulators of the compressors may be connected and disconnected.

In addition to the foregoing, the discharge conduit of each compressor is provided with a blow-off valve 21 that is actuated by a pivoted lever 22. Mounted on the rod 9 that actuates the throttle valve is an adjustable stop 23, for actuating said lever. The stop and lever are so related that the stop can move to and fro to a certain predetermined extent without affecting the position of the lever. The reason for this is that the throttle valve 7 should have a comparatively wide range of operation, whereas the blowoff valve 21 should only be opened when the output of the compressor has reached a certain predetermined low value. To state the matter in another way, the rod 9 is connected to the lever 22 through a lost-motion device or connection. The purpose of a blow-' off valve is to prevent surging or pumping of the fluid undergoing compression. Surging only takes place at light loads, therefore by placing said valve in the dischargeconduits and causing it to open when the load reaches a certain predetermined value, the compressors will always have a certain minimum load which is above that at which surging can take place.

Referring to Figs. 2 and 3, I have shown in detail the construction of the cam 10 and it's actuating parts. The cam in this case comprises a removable plate 25 that is detachably secured to the arms 26 which radiate from a suitable hub, the latter being mounted on the shaft 27 which is carried in suitable bearings. This shaft is provided with a worm-wheel 11 that meshes with and is driven by the worm 12, thelatter being mounted on the shaft 13. 9 indicates the rod that is attached to the regulating valve of the compressor. It is provided with a turn buckle 28 by means of which its length can be readily adjusted. Mounted on the rod is a fork 29 that carries a frame 30. Mounted in the 'frame are rollers 31 and 32, the former engaging the outer surface of the cam and the latter the inner surface; 33 is a compression spring that normally presses the rod 9 outward and away from the frame 30. The frame is provided with pins 34 that travel in slots 35 in the fork and permit of the parts havin a slight relative movement in the direction of the length of the rod 9. This spring 33 forms a compensat- 111g device to compensate for any slight inaccuracies in the construction and prevents overstraining of the parts. By making the cam plate so that it can be readily removed from its support, it may be machined to correspond to the particular characteristics of the compressor with which it is associated.

This would usually be done at installation since it is a very simple operation. Owing to the fact'that the cam 10 of each compressor is connected to the shaft 16 by a coupling, it is a simple matter to cut a compressor out of operation or to modify its operation with respect to the other compressor or compressors feeding into the same header.

The arrangement as illustrated and described in this application has certain features in common with the arrangement shown and described in my Patent No. 1,076,332, dated October 21, 1913.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means.

lVhat I claim as new and desire to secure by Letters Patent of the United States, is

1. In combination, a plurality of centrifugal compressors through which fluid always flows in the same direction, a valve in the inlet of each compressor for throttling the column of fluid as it passes thereto, a.

blow-off valve on the discharge side of each compressor, mechanism for simultaneously moving all of the throttling valves, and a lost motion connection between said mechanism and the blow-off valves so as to operate the blow-off valves when the throttling valves are moved to a predetermined position.

2. In combination, a plurality of centrifugal compressors through which fluid always flows in the same direction, a valve for throttling the column of fluid as it passes through each compressor to a greater or less extent, and mechanism for simultaneously moving all of the valves to vary throttling effects and hence the output of the compressors, and means for individually adjusting the timing of the valves to insure equal amount of fluid being delivered by the compressors.

3. In combination, a plurality of centrifugal compressors through which fluid al ways flows in the same direction, a valve means for each compressor for varying the amount of fluid passing through it without changing its speed, a manually actuated device that is common to all the valve means, and a clutch that is interposed between each valve'means and the actuating device.

-fl. In combination, a plurality of centrifugal compressors connected in parallel as regards the delivery of fluid, a regulator for each compressor which controls the admission pf fluid thereto without changing its speed, a manually actuated device that is common to all the regulators, and a clutch that is interposed between each regulator and the actuating device.

5. In combination, a plurality of centrifugal compressors connected in parallel and through which fluid flows always in the same direction, a regulator for each compressor which is located in its intake pipe for changing its output .without changing its speed, a regulator shaft that is common to all of the compressors, a cam for actuating each of the regulators, means for transmitting movements of the shaft to the cams, a blow-off valve on the discharge side of each compressor, and means including a lost motion connection also operated by the cam for controlling the blow-ofl' valves.

6. In combination, a plurality of centrifugal compressors connected in parallel and through which fluid always flows in the same direction, a regulator for each compressor which is located in its intake pipe for changing its output Without changing its speed, a regulator shaft that is common to all of the compressors, a cam for actuating each of the regulators, means for transmitting movements of the shaft to the cam,

and a clutch located between each regulator and said shaft for connecting and disconnecting them. v I

7. In combination, a plurality of centrifugal compressors connected in parallel, a regulator for each compressor, mechanism for simultaneously actuating the regulators, and a blow-off valve for each compressor that is actuated by said mechanism.

8.'In combination, a plurality of centrif-- ugal compressors connected in parallel, a regulator for each compressor, mechanism for simultaneously actuating the regulators, a blow-off valve for each compressor, and a lost-motion connection between the valves and the said mechanism through which the latter actuates said valves.

9. In combination, a plurality of centrif: ugal compressors connected in parallel to the same receiver, a throttle valve located in the inlet of each compressor, means for I the discharge pipe of each compressor and arranged to be opened under light load conditions, and mechanism that is common to all the regulators and valves for actuating them. I

11. In combination, a plurality of centrifugal compressors arranged to discharge in parallel into the same receiver and through which fluid always flows in the same direction, a regulator for each compressor which changes its output without affecting its speed, a cam for actuating each regulator that is shaped to conform to the characteristic of its compressor, and means for simultaneously moving the cams.

l2. In'combination, a receiver, a plurality of centrifugal compressors connected in parallel. relation thereto as regards the delivery of fluid, a valve meansfor regulating the output of each compressor, a valve means to prevent surging under conditions of light load, and mechanism for simultaneously adjusting the regulating valve means of said compressors for decreasing load conditions and thereafter the surging valve means.

13. In combination, a plurality of centrifugal compressors through. which fluid always passes in the same direction, said compressors being connected in parallel relation as regards the delivery of fluid, regulators for the compressors which control their outputs, means for preventing the amount of fluid passing through the compressors from falling below a predetermined minimum and common means for controlling said regulators and said means.

In witness whereof, I have hereunto set my handthis 26th day of December, 1911. I

RICHARD TROGEB. Witnesses:

IRVING BONEPARTH, HARRY T. PERIssI. 

